Electromagnetic device.



K. C. RANDALL. ELECTROMAGNETIC DEVICE.

APPLICATION FILED MAR. 23. 1914- Patented Oct. 2, 1917.

INVENTOR M /QQMM ATTORNEY n STATES rATENT oFFIon.

c. RANDALL, onnzo'enwoon PARK, PENNSYLVANIA, AssieNo'n T WESTING- nonsn ELECTRIC AND MANUFACTURING COMPANY, A o'oaPoR'A'rIoN or rEN sYL- VANIA.

ELECTROMAGNETIC DEVICE.

igsarasee.

Specification of Letters Patent.

Patented Oct. a, 1917.

Application filed. March 23, 1914. Serial No. 826,555.

To all whom it ma concern:

Be it known that I, KARL RANDALL, aci zen of the-United States, and a resi dent of Edgewood Park, in the county of Allegheny and State'of Pennsylvania, have invented a new and useful Improvement in Electromagnetic Devices, of which the following is a specification.

Y'ltly invention relates to electromagnetic devices and particularly to single-phase electromagnets.

The object of my invention is. to provide an eflicient single-phase electromagnet which shall be noiseless in its operation. Single-phase electrom'agnets, as ordinarily constructed, are noisy in operation, but, if: a single-phase electromagnet is provided with a plurality of windings so designed as to exert their maximum forces at different times, substantially. noiseless operation may be secured.

in the accompanying drawings, Figure 1 is a diagrammatic view of a single-phase electromagnet embodying my invention, Fig. 2 is a similar-view of another form of a singlephase electromagnet adapted for noiseless operation, Fig. 3 is a diagrammatic view of a polyphase electromagnet adapted for noiseless operation, and Fig. 4 is a diagrammatic view showing the rela tions of the windings of the electromagnet shown in Fig 1.

Referring particularly to' Figs. 1 and 4 of the drawing, an electromagnetic device L embodying my invention is connected to a singlephase circuit 1.. The device is comj posed of two electromagnets 2 and 3 comprising,- respectively. stationary core members 2 and 3 .movable core members and 5 connected together by a rod 6, pri mary coils, 7 and 8 connected in series relation, across the circuit 1, and auxiliary coils 9 and 10 of different numbers of turns that are connected together in a closed circuit.

When current flows through the coils "Z" and 8, an eiectromotive force is induced in the coils 9 and 10, but, since the turns of the coils 9 and 10 are not equal, there will be a distortion in the magnetization of the two electromagnet's; This distortion in the magnetization of the .electromagnets will tend to cause theltimes at which the maxi .mum pull occurs in the two eleotromagnets -.;t,o-be different. By properly arranging the stood by those versed in the art.

turns of the coils 9 and 10, one of the electromagnets may be made to exert its Ina-Xi.-

mum pull substantiallyl90 out of phase with the other electromagnet, thus giving an electromagnet which is equivalent to a two-phase electromagnet. The advantage of this may be seen by thoseaversed in the art, by reason of the fact that there is a pull on the movable members of the electromagnet system at all times. If there is a pull on the movable members at all times, i

the chatter-which always accompanies the recurrent energizing and de'e'nergizing of an ordinary single-phaseelectromagnet will be avolded.

The modification of my invention shown in the same manner, one being unbalanced j with respect to the other, their magnetizing forces will be different. By properly changing the number of turns in the winding 16, to which the coil 13 is connected in shunt relation, the unbalancing may be increased.

to such an extent that one magnet will. be

exerting approximately its maximum pull while the other is exerting approximately its minimum pull, thus giving a resultant pull on the movable members thereof at all times and preventing the chattering that usually accompanies the use of a'sin'glephase electromagnet. I

Fig. 3 oi the drawing shows two electromagnets 19 and 20 which are similar to the electromagnets 11 and 12 of Fig. 2 except that the are res ectivel' rovided with coils 21 and 22 connected in shunt relation to the conductors of a three-phase circuit 23.

Since the voltage of one phase of a three phase circuit is out of phase with the voltages of. the other phases, the coils 21 and 22 will exert their. maximum magnetizing forces at different times, as will be under- It will be observed that the. single-phase magnets shown in Figs. 1 and 2 have operating characteristics--and functions that closely resemble those of the poly phase magnet.

It is innnaterial whether the primary windings of my invention are provided with dili'crent numbers of turns and the secondary windings are provided with the same number of turns. or whether the primary windings have the same number of turns and the secondary windings have difierent numbers of turns. It is also immaterial whether both primary and secondary windings have unlike numbers of turns. The essential requirement of my invention is that the ampere turns of each primary winding, when connected in series relation to the other primary winding, shall not be balanced by the resultant ampere turns of its secondary windin when connected as hereinbe'fore explained with respect to Fig. 1, or the ratio of the turns of the coils of one electromagnet must necessarily be different from that of the turns of the coils of the other.

My invention is not limited to the particular construction illustrated but it is capable of various modificaions within the scope of the appended claims.

I claim as my invention:

1. In an electromagnetic device, the combination with two stationary core members and two movable core members, a primary winding for each pair of core members, and a sccoi'idary winding for each pair of core members, the ratios of the nuntibers of turns of the said windings on the respective pairs of core members being different.

'2. An electromagnetic device comprising two stationary core members, two movable core members operatively connected together, rain windings for the pairs of the said core members connected in series relation, and an auxiliary winding for each of the two pairs of core members, the efl'ective ratios of the numbers of turns in the windings on the respective core members being different.

3. An electromagnetic device comprising two stationary core members having the same vertical axis, two movable core mem bers mechanically. connected together, coils for energizing the respective pairs of core members, and auxiliary coils for the respective pairs of members, the effective ratio of the turns in one pair of coils being substantially different from that of the other pair.

4. An electromagnetic device comprising two magnetizable structures, main windings for the said structures connected in series re lation, and auxiliary windings therefor, the effective ratio of the numbers of turns in the windings of one structure being' substantially difi'erent from that of the numbers of turns in the windings of the other structure.

5. In an electromagnetic device, the combination with a plurality of electromagnets,

of means for supplying singlephase electric current thereto, and means for so distorting the magnetizing forces of the said electromagnets that they attain their maximum values alternately at intervals of substantially 9O electrical degrees.

6. In an electromagnetic device, the combination with a plurality of stationary core members, and a plurality of movable core members, of means for energizing the said core members with single-phase electric current, and means inductively related to said energizing means for exerting maximum magnetic force upon the said movable core members alternately at intervals of substantially 9O electrical degrees.

7. In an electromagnetic device, the combination with a plurality of stationary core members, a plurality of movable core members, and magnetizing coils associated therewith, of means for energizing the said coils with singlephase electric current, and means for so distorting the magnetizing forces of the said electromagnets that they attain their maximum values alternately at intervals of substantially 9O electrical degrees, substantially all of the ampere turns of the said coils being capable of exerting tractive force upon the said movable .core members at the said times of maximum magnetizing value.

In testimony whereof, I have hereunto subscribed my name this 19th day of Mar. 1914.

KARL C. RANDALL.

Witnesses:

BERTRAND P. Rown, B. B. HrNEs.

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